package org.ruanjj.collection;

import java.util.*;
import java.util.concurrent.ConcurrentHashMap;

public class main {
    public static void main(String[] args) {
        int[] a = {};
        System.out.println(a.length);

        Vector v = new Vector();
        LinkedList list = new LinkedList();
        list.add("ad");

        HashMap<String,Integer> hashMap = new HashMap<>();

        hashMap.put("Emily",11);
        hashMap.put("Red",12);

        Set<Map.Entry<String, Integer>> entries = hashMap.entrySet();

        System.out.println(entries);

        Hashtable hashtable = new Hashtable();
        ConcurrentHashMap concurrentHashMap = new ConcurrentHashMap();

        Stack<Object> objects = new Stack<>();

        String[] s = new String[10];
        System.out.println(s.length);
    }
}
